I bought 2 used RELs from the same era for 200 bucks each, both in excellent condition. The first was maybe 4 years or so ago and it's a Q150e front firing 10, and the second I found last year and it's Q108EII. My system was absolutely energized by the first and made even better by the second. Musical subs simply require that you move 'em around until YOU like the sound, and pay attention to the crossover points and levels on the subs (I find using a test CD to determine the ACTUAL low frequency limits of my mains is useful, and set the subs to take over around the point the mains stop delivering useful bass). I personally don't care about room EQ gizmos as you wind up surrendering EQ choices to the people who design these digital nannies, and I'm a seriously experienced live sound engineer who's ego won't allow such intrusions. Plus my largish listening room has tall, sloped ceilings and furniture. I turn the subs up and down if needed, and seriously enjoy the living bejeezus out of them every day.